Transparent conductive film roll and production method thereof, touch panel using the same, and non-contact surface resistance measuring device

ABSTRACT

A transparent conductive film roll which has a transparent conductive layer on at least one surface thereof and has an excellent distribution uniformity of surface resistance in longitudinal and lateral directions thereof wherein the distribution uniformity D of surface resistance defined by the following expression (1) is 0.2 or less when the surface resistance of the transparent conductive layer is measured at a total of 33 points within the film roll, and therefore, is suitable especially for a large panel,
 
 D= ( R max− R min)/( R max+ R min)  (1)
 
where Rmax and Rmin represent the maximum and minimum values of 33 surface resistance measurement values.

This is a continuation application of U.S. patent application Ser. No.10/481,235 filed on 30 Jul. 2004, now U.S. Pat. No. 7,436,190, which isa 371 national phase application of PCT/JP02/05871 filed on 13 Jun.2002, claiming priority to JP 2001-188556, filed on 21 Jun. 2001, and JP2001-319735 filed on 17 Oct. 2001, the contents of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a transparent conductive film rollwhich is a roll of transparent conductive film, in which a transparentconductive layer is laminated on a plastic film, and a production methodthereof, and a touch panel using the same and a non-contact surfaceresistance measuring device. More particularly, the present inventionrelates to a long transparent conductive film roll having a uniformsurface resistance distribution in a longitudinal direction thereof andin a lateral direction thereof, which is suitable for a transparentelectrode for a touch panel or an electroluminescence panel whichrequires transparency and conductivity, particularly a transparentelectrode for a large panel, and a touch panel using the same and anon-contact surface resistance measuring device.

BACKGROUND ART

As a transparent conductive film, a film comprising a plastic film and aconductive material provided thereon is commonly used. As the conductivematerial, either organic or inorganic materials can be used. Inorganicmaterials are preferable in terms of both conductivity and transparency.As the inorganic material, metals, such as gold, silver and the like,and metal oxides are preferable in terms of transparency. Among metaloxides, indium oxide, tin oxide, zinc oxide, and mixed oxides thereofare particularly preferable. Films in which the above-described metaloxide is deposited on a plastic film using a vapor deposition method, anion plating method, a sputtering method or a CVD method, are known.

Transparent conductive films are generally produced by an ion platingdevice or a sputtering device which roll up a film. A transparentconductive film roll produced by the above-described device is cut by aslitter into pieces having a size of about 300 to 800 mm in width andabout 10 to 1000 m in length, which are in turn rolled up by a papertube or plastic core. Thus, the transparent conductive film is generallycirculated in the form of a film roll. After a film roll in which a filmis rolled up is cut into sheets, silver paste printing, dielectricprinting or the like is performed on the film so that the resultant filmis used as a transparent electrode for a tough panel or anelectroluminescence panel.

In analog touch panels, the position of an input is recognized andcharacters or symbols are displayed, assuming that the distribution ofsurface resistance of a transparent electrode thereof is uniform(“Gekkan Disupurei [Monthly Display”, September 1999, p. 82). Therefore,the surface resistance of a transparent conductive film used thereinneeds to be uniformly distributed at any position thereof. Also, in thecase of transparent electrodes of electroluminescence panels, atransparent electrode having a uniform surface resistance distributionis required to obtain uniform light emission intensity within the panel.In particular, as the size of an electroluminescence panel is increased,the higher degree of uniformity is required for the distribution ofsurface resistance of a transparent electrode thereof.

The distribution of surface resistance of a transparent electrode can bemade uniform as follows. A surface resistance measuring device isprovided in a rolled-up film forming device. The surface resistance of atransparent conductive layer is sequentially measured in-line whileforming the transparent conductive layer. Conditions for forming thetransparent conductive layer are regulated so that the surfaceresistance thereof is uniformly distributed.

An example of the above-described method includes a method forcontacting and sandwiching a transparent conductive film between twometal rollers and measuring the surface resistance between the rollers.However, in principle, this method can measure the distribution ofsurface resistance of a transparent conductive film in a longitudinaldirection thereof, but not the surface resistance distribution in alateral direction thereof. Concerning the surface resistancedistribution in a longitudinal direction thereof, if the tension of thefilm is not uniform, the contact between the metal rolls and thetransparent conductive layer is not uniform, leading to errors in themeasurement of the surface resistance.

There is also a method for measuring the surface resistance of atransparent conductive film in a lateral direction thereof, in whichthree or more metal rings are provided around an insulated roller (madeof silicone rubber or polytetrafluoroethylene) and the resistancebetween each metal ring is measured. However, a small protrusion isformed between the insulator and the metal ring, which is likely todamage the film surface.

Therefore, as a surface resistance measuring device which cansequentially measure the surface resistance distribution in a lateraldirection thereof and does not damage the film surface, a method formeasuring a coupled inductance between an electromagnetic induction coiland a conductive film (a method for applying magnetic field andmeasuring a resulting eddy current) is known (“Gekkan Disupurei [MonthlyDisplay”, September 1999, p. 88). In this method, however, aconsiderably high intensity of applied magnetic field is required forthe measurement of a conductive film having a surface resistance of 10Ω/□ or more. In this case, the spread of magnetic flux is large, leadingto the path line fluctuation of a substrate in a production process(vibration in a direction normal to a surface of the substrate). Thus, adistance between a sensor section and a conductive film to be measuredfluctuates and the coupled inductance is not constant. As a result, thein-line sequential measurement has large measurement errors.

Further, in this method, the magnetic permeability of a ferrite coilwhich functions as an eddy current generating section or an eddy currentdetecting section has a temperature dependency. The inductance ischanged in accordance with, if any, the fluctuation of the temperature.Therefore, even if a high frequency voltage applied to the coil isconstant, an eddy current flowing through the conductive film ischanged, resulting in large measurement errors.

As described above, even if a general surface resistance measuringdevice is provided in a rolling up device, large measurement errors makeit considerably difficult to obtain a transparent conductive film rollhaving uniform surface resistance.

The present invention was made, taking the above-described circumstancesinto consideration. An object of the present invention is to provide atransparent conductive film roll having a uniform surface resistancedistribution in a longitudinal direction thereof and in a lateraldirection thereof; a production method thereof; and a touch panelproduced using the same.

DISCLOSURE OF THE INVENTION

A transparent conductive film roll of the present invention is obtainedby rolling up a plastic film having a transparent conductive layer on atleast one side thereof. A width thereof is 300 to 1300 mm and a lengththereof is 10 to 1000 m. When the surface resistance (Ω/˜) of thetransparent conductive layer is measured at a total of 33 pointsincluding positions located at a middle in a lateral direction thereofand any positions located at a distance of from 25 to 100 mm fromlateral ends thereof, the positions being separated in intervals of 1/10of a full length in a longitudinal direction thereof, the distributionuniformity D of the surface resistance is 0.20 or less. The distributionuniformity D is represented by expression (1):D=(Rmax−Rmin)/(Rmax+Rmin)  (1)where Rmax and Rmin represent the maximum and minimum surface resistancevalues measured at the 33 points, respectively. The closer to zero thedistribution uniformity D of the surface resistance, the smaller thefluctuation of the surface resistance.

A touch panel of the present invention comprises a pair of panel plateshaving a transparent conductive layer. The panel plates are disposed viaa spacer so that the transparent conductive layers face each other. Atleast one of the panel plates is a transparent conductive film obtainedby cutting the above-described transparent conductive film roll.

A method of the present invention is provided for producing atransparent conductive film roll having a transparent conductive layeron at least one side thereof using a rolled-up film forming device. Therolled-up film forming device has anon-contact surface resistancemeasuring device therewithin. The surface resistance of the transparentconductive layer is sequentially measured in line at a plurality ofposition in each of longitudinal and lateral directions of the filmwhile forming the transparent conductive layer. Conditions for formingthe transparent conductive layer are regulated so that the surfaceresistance thereof is uniformly distributed. The non-contact surfaceresistance measuring device of the present invention mainly comprises aneddy current generating section which is placed at a predetermineddistance from the transparent conductive layer, faces the transparentconductive layer and flows an eddy current in the transparent conductivelayer, an eddy current detecting section which is separated from thetransparent conductive layer and detects the eddy current flowingthrough the transparent conductive layer, a temperature detectingsection which detects a temperature of the eddy current generatingsection or the eddy current detecting section, and a calculating meanswhich calculates a surface resistance of the transparent conductivelayer based on a result of detection by the eddy current detectingsection and a result of detection by the temperature detecting sectionwhere a voltage applied to the eddy current generating section isconstant. When the result of detection by the temperature detectingsection is deviated from a reference temperature, the calculating meanscalculates an amount of an increase or decrease in the eddy currentcaused by the deviation from the reference temperature and adds orsubtracts the amount of the increase or decrease in the eddy current toor from the result of detection by the eddy current detecting section tocorrect the value of the eddy current and calculates the surfaceresistance of the transparent conductive layer based on the correctedvalue of the eddy current.

A non-contact surface resistance measuring device of the presentinvention mainly comprises an eddy current generating section which isplaced at a predetermined distance from the transparent conductivelayer, faces the transparent conductive layer and flows an eddy currentin the transparent conductive layer, an eddy current detecting sectionwhich is separated from the transparent conductive layer and detects theeddy current flowing through the transparent conductive layer, atemperature detecting section which detects a temperature of the eddycurrent generating section or the eddy current detecting section, and acalculating means which calculates a surface resistance of thetransparent conductive layer based on a result of detection by the eddycurrent detecting section and a result of detection by the temperaturedetecting section where a voltage applied to the eddy current generatingsection is constant. When the result of detection by the temperaturedetecting section is deviated from a reference temperature, thecalculating means calculates an amount of an increase or decrease in theeddy current caused by the deviation from the reference temperature andadds or subtracts the amount of the increase or decrease in the eddycurrent to or from the result of detection by the eddy current detectingsection to correct the value of the eddy current and calculates thesurface resistance of the transparent conductive layer based on thecorrected value of the eddy current.

The plastic film used as the substrate for the transparent conductivefilm roll of the present invention is obtained by extruding an organicpolymer in a molten or solution state and optionally stretching thepolymer in a longitudinal and/or lateral directions thereof, cooling andannealing the polymer.

Examples of such an organic polymer include polyethylenes,polypropylenes, polyethylene terephthalates,polyethylene-2,6-naphthalates, polypropylene terephthalates, nylon 6,nylon 4, nylon 6.6, nylon 12, polyimides, polyamideimides,polyethersulfanes, polyetheretherketones, polycarbonates, polyarylates,cellulose propionates, polyvinyl chlorides, polyvinylidene chlorides,polyvinyl alcohols, polyetherimides, polyphenylene sulfides,polyphenylene oxides, polystyrenes, syndiotactic polystyrenes,norbornene polymers, and the like.

Among these organic polymers, polyethylene terephthalates, polypropyleneterephthalates, polyethylene-2,6-naphthalates, syndiotacticpolystyrenes, norbornene polymers, polycarbonates, polyarylates, and thelike are preferable. These organic polymers may be used as homopolymeror may be copolymerized with a small amount of monomers of other organicpolymers. Also, these organic polymers may be blended with one or morekinds of other organic polymers.

The above-described plastic film needs to have an excellent level oftransparency in view of the visibility of a panel. Therefore, it ispreferable that particles, additives or the like which worsen thetransparency are not contained in the plastic film. However, the filmsurface preferably has an appropriate level of surface roughness in viewof handling ability (sliding ability, running ability, blocking ability,ability to purge accompanying air when rolling up, etc.) in producing aplastic film and unrolling or rolling a roll.

To meet mutually contradictory characteristics, a substrate film havinga layered structure is produced by a coating method or coextrudingmethod, where the thickness of the film is considerably small, i.e.,0.03 to 1 μm and particles are contained only in a surface layer. Amongthese methods, the coating method is preferable. This is because thecoating method can produce a film thinner than that made by thecoextruding method, so that the adhesion between the plastic film and aconducting layer can be satisfactory.

When a layered plastic film is used as a substrate, one or more kinds ofparticles may be contained in a surface layer thereof. Particles havinga refractive index equal or close to that of a component resin of theplastic film and a binder resin of a coat layer thereof are preferablein view of the transparency thereof. For example, when a polyester-basedresin is used as a binder resin in the substrate or the coat layer, 0.5to 5.0% by weight of particles (e.g., silica, glass filler, mixed oxidesuch as alumina-silica, etc.) having an average diameter of 10 to 200 nmare preferably contained in the binder resin.

The thickness of the plastic film is preferably in the range of morethan 10 μm and no more than 300 μm, particularly preferably in the rangeof from 70 to 260 μm. When the thickness of the plastic film is no morethan 10 μm, the mechanical strength is insufficient. In this case,particularly, when the plastic film is used in a touch panel, the filmis likely to be significantly deformed by a stylus input, resulting ininsufficient durability. When the thickness exceeds 300 μm, it isdifficult to roll up the film.

The surface of the above-described plastic film may be subjected tosurface activating treatment, such as corona discharge treatment, glowdischarge treatment, flame treatment, ultraviolet irradiation treatment,electron beam irradiation treatment, ozone treatment, or the like, to anextent which does not impair the object of the present invention.

A curable resin cured material layer or an inorganic thin film layer maybe provided between the substrate plastic film and the transparentconductive layer so as to improve the adhesiveness of the transparentconductive layer. The curable resin may not be particularly limited aslong as the resin is capable of being cured by applying energy, such asheating, ultraviolet irradiation, electron beam irradiation, or thelike. Examples of the curable resin include silicone resins, acrylicresins, methacrylic resins, epoxy resins, melamine resins, polyesterresins, urethane resins, and the like. An ultraviolet curable resin ispreferably a major component in view of productivity.

The transparent conductive layer used in the present invention is notparticularly limited as long as the transparent conductive layer is madeof a material having both transparency and conductivity. Examples of thetransparent conductive layer include a monolayer structure or a layeredstructure having two or more layers, which are made of indium oxide, tinoxide, zinc oxide, indium-tin mixed oxides, tin-antimony mixed oxides,zinc-aluminum mixed oxides, indium-zinc mixed oxides, silver and silveralloys, copper and copper alloys, gold, or the like. Among them,indium-tin mixed oxides or tin-antimony mixed oxides are preferable inview of environmental stability or circuit workability.

In order to adjust the surface resistance or the transparency, thetransparent conductive layer may contain at least one of titanium oxide,cerium oxide, tungsten oxide, niobe oxide, yttrium oxide, zirconiumoxide, silicon oxide, zinc oxide, gallium oxide, aluminum oxide,antimony oxide, tantalum oxide, hafnium oxide, samarium oxide, and thelike. The total amount of the inorganic oxide contents is preferably 10%by weight or less with respect to the major component of the transparentconductive layer.

The thickness of the transparent conductive layer is preferably in therange of from 4 to 800 nm, particularly preferably from 5 to 500 nm.When the transparent conductive layer has a thickness of less than 4 nm,it is difficult to produce a continuous thin film and the transparentconductive layer tends not to have a satisfactory level of conductivity.When the thickness is more than 800 nm, the transparency is likely to bereduced.

Examples of a known method for forming a transparent conductive layer ofthe present invention include a vacuum deposition method, a sputteringmethod, a CVD method, an ion plating method, a spraying method, and thelike. Among these methods, an appropriate method may be selecteddepending on a required thickness.

Examples of the sputtering method include a typical sputtering methodusing an oxide target, a reactive sputtering method using a metaltarget, and the like. In this case, a reactive gas, such as oxygen,nitrogen or the like, may be introduced, or a technique, such as ozoneaddition, plasma irradiation, ion assist or the like, may be used incombination with the sputtering method. A bias, such as direct current,alternating current, high frequency or the like, may be applied to thesubstrate to such an extent that the object of the present invention isnot impaired.

A monolayer or a multilayer made of a material having a refractive indexdifferent from that of the transparent conductive layer may bepreferably provided between the transparent conductive layer and theplastic film so as to reduce the light reflectance of the transparentconductive film at a surface of the transparent conductive layer andimprove the light transmittance thereof. In the case of the monolayer, amaterial having a refractive index smaller than that of the transparentconductive layer is preferably used. In the case of a multilayeredstructure having two or more layers, a layer adjacent to the plasticfilm may be made of a material having a refractive index greater thanthat of the plastic film while a layer underlying the transparentconductive layer may be made of a material having a refractive indexsmaller than that of the transparent conductive layer.

The above-described material for low reflection treatment is notparticularly limited to organic or inorganic materials as long as thematerial satisfies the above-described relationship between therefractive indexes. Examples of the material include dielectricmaterials, such as CaF₂, MgF₂, NaAlF₄, SiO₂, ThF₄, ZrO₂, Nd₂O₃, SnO₂,TiO₂, CeO₂, ZnS, In₂O₃, and the like.

A transparent conductive film roll of the present invention has auniform surface resistance distribution in longitudinal and lateraldirections thereof, where a distribution uniformity D of the surfaceresistance is 0.20 or less, the distribution uniformity D beingrepresented by expression (1):D=(Rmax−Rmin)/(Rmax+Rmin)  (1).

In a transparent conductive film roll produced by the above-describedmaterial and method, the surface resistance distribution is made uniformin longitudinal and lateral directions thereof by using an in-line andnon-contact surface resistance measuring device described below which isprovided in a rolled-up film forming device in the step of providing atransparent conductive layer.

A configuration of the non-contact surface resistance measuring devicewill be described with reference to FIG. 1.

The non-contact surface resistance measuring device comprises aplurality (n) of eddy current sensors 3 which are placed at apredetermined distance from a conductive layer 2 on a substrate 1 andfaces the conductive layer 2. The eddy current sensor 3 comprises aneddy current generating section which flows an eddy current in theconductive layer 2, and an eddy current detecting section (integratedwith the eddy current generating section of the eddy current sensor 3)which is separated from the conductive layer 2 and detects the eddycurrent flowing through the conductive layer 2. A temperature sensor 4A(corresponding to a temperature detecting section) which detects atemperature of the eddy current sensor 3 and a separation distancesensor 4B which detects the distance between the eddy current sensor 3and the conductive layer 2 are integrated with the eddy current sensor3. The non-contact surface resistance measuring device further comprisesa computer 7 (corresponding to a calculation means) which calculates thesurface resistance of the conductive layer 2 based on the results ofdetection by the eddy current detecting section of the eddy currentsensor 3 and the results of detection by the temperature sensor 4A andthe separation distance sensor 4B.

The eddy current sensor 3, the temperature sensor 4A and the separationdistance sensor 4B are each connected to a sensor amplifier 6. Thesensor amplifier 6 comprises a high frequency oscillator, an A/Dconverting means which converts an analog signal of an eddy current to adigital signal, an A/D converting means which converts an analog signalcorresponding to a separation distance between the conductive layer 2and the sensor 3 to a digital signal, and an A/D converting means whichconverts an analog signal corresponding to a temperature to a digitalsignal. The high frequency oscillator applies a high frequency to theconductive layer and detects an eddy current flowing through theconductive layer.

Preferably, the separation distance sensor 4B which detects a separationdistance between the conductive layer 2 and the sensor 3 is adisplacement sensor of capacitance type, ultrasonic type, laser type,photoelectric type or the like. The means which calculates the surfaceresistance of a conductive layer is based on a digital signal.

A method of flowing an eddy current in a conductive layer is achieved byproviding an eddy current generating section and an eddy currentdetecting section so that they are located a predetermined distance fromthe conductive layer and face the conductive layer, or by sandwichingthe conductive film by an eddy current generating section and an eddycurrent detecting section. For example, a high frequency voltage isapplied to a coil, such as a ferrite coil or the like, which functionsas an eddy current generating section, and the coil is moved close to aconductive layer, or a conductive film is sandwiched by the coil to flowan eddy current in the conductive layer due to high frequency inductivecoupling.

When a high frequency voltage is constant, an eddy current flowing inthe conductive layer is inversely proportional to the surface resistanceof the conductive layer. Therefore, if a calibration curve is previouslyprovided for a relationship between eddy current and surface resistance,a surface resistance can be obtained at a separation distance (referencepoint).

In principle, an eddy current tends to be decreased with an increase ina separation distance between a conductive layer and a sensor. Apre-prepared calibration curve is provided for a relationship betweeneddy current and a separation distance. Specifically, a means whichdetects the separation distance between a conductive layer and a sensoris used to obtain a separation distance. A difference between theseparation distance and a reference point is obtained. A correctionvalue is calculated for an eddy current based on the calibration curve.The correction value is subtracted when the separation distance betweena conductive layer and a sensor is smaller than the reference point,while the correction value is added when the separation distance betweena conductive layer and a sensor is greater than the reference point.Thus, the surface resistance of a conductive layer can be accuratelycalculated at any separation distance between the conductive layer and asensor. The calculation of the surface resistance of a conductive layeris sequentially performed in a production process of the conductivelayer in accordance with the operation cycles of a computer.

In principle, the magnetic permeability of a coil which functions as aneddy current generating section or an eddy current detecting section hasa temperature dependency. Therefore, an eddy current is changed inaccordance with, if any, temperature fluctuation. There is a positivecorrelation between eddy current and magnetic permeability. There areboth positive and negative temperature dependencies of the magneticpermeability of a coil depending on the type of the coil material.Specifically, the positive dependency means that the magneticpermeability is increased with an increase in the temperature. Thenegative dependency means that the magnetic permeability is decreasedwith an increase in the temperature.

Therefore, when the result of detection by the temperature sensor 4A isdeviated from the reference temperature, the calculating means obtainsthe amount of an increase or decrease in an eddy current caused by thedeviation from the reference temperature based on the temperaturedependency of a selected coil material. In addition, the amount of anincrease or decrease in the eddy current is subtracted from or added tothe detection result by the eddy current detecting section of the eddycurrent sensor 3 to correct the value of the eddy current. The surfaceresistance is calculated based on the corrected value of the eddycurrent.

In this case, it is important to previously prepare a calibration curvefor a relationship between temperature fluctuations and corrected eddycurrent amounts.

Thus, the surface resistance of a conductive layer is calculated basedon a previously prepared calibration curve. Therefore, even when thetemperature of an eddy current generating section fluctuates, an erroris unlikely to occur in the measurement value of the surface resistanceof a conductive layer.

By providing a plurality of eddy current generating sections and eddycurrent detecting sections in a lateral direction of a conductive layerin a production process thereof, the surface resistance of theconductive layer in the lateral direction can be accurately measuredeven if there is a temperature distribution (uneven temperature) in thelateral direction due to the large width.

The eddy current sensor 3, the temperature sensor 4A and the separationdistance sensor 4B are connected via a sensor cable 5 to the sensoramplifier 6. A CRT 8 which displays a measurement result, a printer 9which produces printed outputs of the measurement result, and an alarmdevice 10 which reports to an operator that a measured surfaceresistance exceeds a predetermined range, or an abnormality, areprovided.

The sensor amplifier 6 is provided with a high frequency oscillator, afirst A/D converter which converts an analog signal of an eddy currentto a digital signal, and a second A/D converter which converts an analogsignal corresponding to the temperature to a digital signal.

The computer 7 processes data based on digital signals obtained by thefirst and second A/D converters. When a detection result of thetemperature sensor 4A is deviated from the reference temperature, thecomputer 7 obtains the amount of an increase or decrease in an eddycurrent caused by the deviation from the reference temperature, adds orsubtracts the amount of the increase or decrease in the eddy current toor from a detection result of the eddy current detecting section of theeddy current sensor 3 to correct the value of the eddy current, andcalculates the surface resistance of the conductive layer 2 based on thecorrected value of the eddy current. This calculation method will bedescribed in detail below.

In a production process for the conductive layer 2, a plurality ofnon-contact surface resistance measuring devices are provided in alateral direction of the conductive layer 2 or the non-contact surfaceresistance measuring device is continuously reciprocated in the lateraldirection of the conductive layer 2. Thereby, a surface resistancedistribution in the lateral direction of the conductive layer 2 of atransparent conductive film roll or a trend (changes over time) of thesurface resistance in a longitudinal direction of the conductive layer 2can be obtained by the computer 7.

Next, an operation of the non-contact surface resistance measuringdevice will be described below.

(1) The eddy current sensor 3, the temperature sensor 4A and theseparation distance sensor 4B are placed such that the eddy currentgenerating sections of the eddy current sensor 3 faces the conductivelayer 2 on the substrate 1 at a predetermined distance of severalmillimeters from the conductive layer 2, or such that the eddy currentgenerating sections of the eddy current sensor 3 sandwich the substrate1.

(2) A high frequency is applied from the sensor amplifier 6 to the eddycurrent generating section of the eddy current sensor 3 to generate aneddy current in the conductive layer 2 due to high frequency inductioncoupling.

(3) When the applied high frequency voltage is controlled to beconstant, an eddy current flowing in the conductive layer 2 is inverselyproportional to the surface resistance of the conductive layer 2.Therefore, if a calibration curve is previously provided for arelationship between eddy current and surface resistance as shown inFIG. 2, a surface resistance of an unknown conductive layer 2 can beobtained at the reference temperature where the conductive layer 2 andthe eddy current generating section of the eddy current sensor 3 areseparated at the predetermined distance.

(4) An eddy current is increased if the temperature dependency of a coilmaterial is a positive dependency. Thus, a surface resistance tends tobe small. Therefore, the detection result of the eddy current detectingsection of the eddy current sensor 3 is corrected based on thepreviously prepared calibration curve for the relationship betweensurface resistance and temperature as shown in FIG. 3.

The correction method will be described in detail below.

For example, it is assumed that a conductive layer has a surfaceresistance of 50 Ω/□ at a reference temperature of 25° C. If thetemperature is increased to 30° C., the surface resistance is about 40Ω/□, so that the measured value is decreased by 20% from the actualsurface resistance. This relationship is represented by expression (2)below.Y=−0.0458X ²+0.2404X+72.9  (2)where the X axis represents ambient temperature (° C.) and the Y axisrepresents the measured value of the surface resistance (Ω/□).

For example, if 30(° C.) is substituted for X in expression (2), Y iscalculated to be 38.9 (Ω/□). A surface resistance is 50 Ω/□ at areference temperature of 25° C. Therefore, a correction amount is 11.1Ω/□. The correction amount is added to Y, resulting in a measurementresult of 50 Ω/□.

Conversely, if an ambient temperature is decreased to 20° C., 20(° C.)is substituted for X in expression (2). In this case, Y=59.4 (Ω/□).Therefore, a correction amount is 9.4 Ω/□. The correction amount issubtracted from Y, resulting in a measurement result of 50 Ω/□.

The addition and subtraction of a correction amount are previouslydetermined depending on the temperature dependency of a material for aconductive layer. With this correction technique, an error in surfaceresistance measurement can be reduced even if temperature fluctuates.

Thus, an accurate correction value can be obtained by previouslypreparing a calibration curve as shown in FIG. 3 for the conductivelayer 2 having known surface resistance.

(5) A surface resistance tends to be decreased with an increase in theseparation distance between the eddy current sensor and the conductivelayer. The calculation result obtained in (4) is corrected based on acalibration curve for the relationship between surface resistance andseparation distance shown in FIG. 4.

The surface resistance of the conductive layer 2 is displayed on the CRT6 by the computer 7 using any software. The surface resistance is usedas a measured value or a graph in data processing. The surfaceresistance is sequentially measured in line. The surface resistance isoptionally printed out by the printer 9.

The calculation of the surface resistance of the conductive layer 2 canbe sequentially performed in a production process of the conductivelayer 2 in accordance with the operation cycles of the computer 7.

By feeding the measurement result of the surface resistance back to thealarm device 10 or a production process, the surface resistance can becontrolled in production of a transparent conductive film roll. Thereby,the quality and productivity in production process can be improved.

By integrating the eddy current sensor 3, the temperature sensor 4A andthe separation distance sensor 4B together, the eddy current and thetemperature can be measured at substantially the same point. Thereby,measurement accuracy can be improved.

Other preferred embodiments of the non-contact surface resistancemeasuring device will be described below.

In a small production device in which the width of the conductive layer2 is from about 300 to 500 mm during a production process, a temperaturedistribution (uneven temperature) in a lateral direction is relativelysmall and it is considered that temperature fluctuation occurssubstantially uniformly. When such a small production device is used toproduce the conductive layer 2, it is possible that only a singletemperature sensor 4A is provided for a plurality of eddy currentsensors 3.

Specifically, the number of the temperature sensors 4A is made smallerthan the number of the eddy current generating sections of the eddycurrent sensor 3, thereby making it possible to suppress the cost of thetemperature sensor 4A to a low level.

It is preferable that the temperature sensor 4A has a high resolutionand a satisfactory level of accuracy or responsiveness. If theresolution is 0.2° C. or less and the accuracy is ±3% or less, a moreaccurate measurement result can be obtained.

The eddy current sensor 3 and the temperature sensor 4A may be providedseparately. The eddy current generating section of the eddy currentsensor 3 and the eddy current detecting section of the eddy currentsensor 3 may be provided separately and the eddy current generatingsection of the eddy current sensor 3 is provided on the side of theconductive layer 2 while the eddy current detecting section of the eddycurrent sensor 3 and the temperature sensor 4A are provided on the sideof the substrate 1.

If a calibration curve is drawn based on data measured in the range offrom 10° C. to 40° C. in 1° C. steps, a more accurate result can beobtained, though a temperature range used for correction is not limitedto the values described in the embodiments. It is preferable topreviously prepare a calibration curve indicating a relationship betweensurface resistance and temperature for each product sample.

The temperature sensor 4A can be composed of a temperature sensor, suchas a thermocouple sensor, a resistance sensor, a thermocouple, aninfrared sensor or the like.

As the computer 7, a panel computer, a personal computer, a factorycomputer or the like can be used.

The numbers of the eddy current generating sections of the eddy currentsensor 3, the eddy current detecting sections of the eddy current sensor3 and the temperature sensors 4A are not limited to the values describedin the above-described embodiments and may be changed as appropriate.

The transparent conductive film roll of the present invention is cut bya slitter into pieces having a width of from about 300 to 800 mm and alength of from about 10 to 1000 m. The film is subjected to silver pasteprinting, dielectric printing or the like, resulting in a transparentelectrode for used in a touch panel or electroluminescence panel.

FIG. 11 shows an exemplary analog stylus input touch panel comprising atransparent conductive film obtained by cutting a transparent conductivefilm roll of the present invention. This touch panel comprises a pair ofpanel plates having a transparent conductive layer, which are disposedvia a spacer so that the transparent conductive layers are opposed toeach other, where at least one of the panel plates is a transparentconductive film obtained by cutting a transparent conductive film rollof the present invention.

When a stylus is used to input a character or pattern on the touchpanel, a stylus pressure allows the opposing transparent conductivelayers to contact each other, resulting in an electrically ON state.Therefore, the position of the stylus can be detected on the touchpanel. By detecting the position of the stylus sequentially andaccurately, characters can be recognized from the trace of the stylus.

In this case, a transparent conductive film obtained by cutting atransparent conductive film roll of the present invention is provided ona panel plate which contacts a stylus. A surface resistance issubstantially uniform in longitudinal and lateral directions of thetransparent conductive film. Therefore, a stable touch panel having asmall character or pattern recognition deviation rate can be obtained nomatter what portion of the transparent conductive film roll is used.

Alternatively, a transparent conductive film obtained by cutting atransparent conductive film roll of the present invention is provided onboth panels of an analog stylus input touch panel. A transparent resinsheet is provided via an adhesive agent on a surface of the transparentconductive film on which a conductive layer is not deposited. Thus, atransparent conductive layered sheet for use in a fixed electrode for atouch panel is obtained. By using a fixed electrode made of a resininstead of one made of glass, a touch panel which is light and isdifficult to break due to shock can be produced.

The above-described adhesive agent is not particularly limited as longas it has transparency. Preferably examples of the adhesive agentinclude acrylic-based adhesive agents, silicone-based adhesive agents,rubber-based adhesive agents, and the like. The thickness of theadhesive agent is preferably in the range of from 1 to 100 μm, though itis not particularly limited. When the adhesive agent has a thickness ofless than 1 μm, it is difficult to obtain adhesiveness without anypractical problem. When the adhesive agent has a thickness of more than100 μm, the adhesive agent is not preferable in view of productivity.

The transparent resin sheet attached via the adhesive agent is used toprovide a mechanical strength equal to that of glass. The transparentresin sheet preferably has a thickness of from 0.05 to 5 mm. When thetransparent resin sheet has a thickness of less than 0.05 mm, themechanical strength thereof is not satisfactory compared to that ofglass. When the transparent resin sheet has a thickness of more than 5mm, the transparent resin sheet is too thick to be suitable for a touchpanel. Materials for the above-described transparent plastic film can beused as materials for the transparent resin sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram for explaining a configuration of a non-contactsurface resistance measuring device.

FIG. 2 is a diagram for explaining a calibration curve indicating arelationship between eddy current and surface resistance.

FIG. 3 is a diagram for explaining a calibration curve indicating arelationship between temperature and surface resistance.

FIG. 4 is a diagram for explaining a calibration curve indicating arelationship between eddy current and separation distance.

FIG. 5 is a diagram for explaining a surface resistance distribution ina slit roll in Example 1.

FIG. 6 is a diagram for explaining a surface resistance distribution ina slit roll in Example 2.

FIG. 7 is a diagram for explaining a surface resistance distribution ina slit roll in Example 3.

FIG. 8 is a diagram for explaining a surface resistance distribution ina slit roll in Example 4.

FIG. 9 is a diagram for explaining a surface resistance distribution ina slit roll in Comparative Example 1.

FIG. 10 is a diagram for explaining a surface resistance distribution ina slit roll in Comparative Example 2.

FIG. 11 is a diagram for explaining an output shape of the touch panelof Example 1.

FIG. 12 is a diagram for explaining an output shape of the touch panelof Comparative Example 1.

FIG. 13 is a cross-sectional view of the touch panel of Example 1.

FIG. 14 is a diagram for explaining a surface resistance distribution ina slit roll in Example 5.

DESCRIPTION OF REFERENCE NUMERALS

1 substrate

2 conductive layer

3 eddy current sensor

4A temperature sensor

4B separation distance sensor

5 sensor cable

6 sensor amplifier

7 computer

8 CRT

9 printer

10 alarm device

11 communication cable

12 CRT cable

13 printer cable

14 control cable

15 pattern recognized by a touch panel

16 transparent conductive film

17 plastic film

18 transparent conductive layer

19 glass plate

20 beads

EXAMPLES

Hereinafter, the present invention will be described by way ofillustrative examples and comparative examples, though the presentinvention is not limited to the examples below. Characteristics oftransparent conductive film rolls and touch panels obtained in theexamples were assessed by a method described below.

(1) The Surface Resistance of a Transparent Conductive Layer

The surface resistance of a transparent conductive layer was measured bya 4-pin probe method using a surface resistance measuring device (LotestAMCP-T400 manufactured by Mitsubishi Petrochemical) in accordance withJIS-K7194, where measurement was performed at points which were locatedat a middle portion in a lateral direction of a slit roll of transparentconductive film and points which were located at a distance of 200 mmfrom the middle portion to the right and left, and these points wereseparated in 10 m intervals in a longitudinal direction.

Specifically, the surface resistance of the slit roll was measured at 33points (3 points in the lateral direction×11 points in the longitudinaldirection) in a slit roll. The maximum and minimum values of 33measurement values were represented by Rmax and Rmin, respectively.These values were used to calculate the distribution uniformity D of thesurface resistance (=(Rmax−Rmin)/(Rmax+Rmin)). This calculation wasperformed for a total of 16 slit rolls.

(2) The Pattern Recognition Deviation Rate of a Touch Panel

Five circles having a diameter of 40 mm were written on a touch panelproduced as described above using an X-Y plotter (DXY-1150A manufacturedby Roland). The tip of a pen of the plotter had a size of 0.8 mmΦ andwas made of polyacetal and the pen load was 0.6 N. Signals were readfrom the silver paste and it was assessed whether or not the circleswere correctly recognized. A pattern recognition deviation rate (%) wascalculated by (|r1−r0|/r0)×100, where the length of the major axis of arecognized mark is represented by r1 and the diameter of the writtencircle is represented by r0 (=40 mm). The pattern recognition deviationrate was calculated for the five written points. The highest deviationrate was defined as the pattern recognition deviation rate of the touchpanel.

Example 1

A sputtering and rolling up device comprising non-contact surfaceresistance measuring devices incorporating a temperature sensor and aseparation distance sensor as shown in FIG. 1 was used and an ITO target(containing 10% by weight of tin oxide, manufactured by Mitsui Miningand Smelting) was employed. Note that the non-contact surface resistancemeasuring device was provided at three points: a middle portion in alateral direction of a film; and at a distance of 500 mm from the middleportion to the right and left. A PET film roll having a size of 1300 mmin width, 850 m in length and 188 μm in thickness and having anadhesion-modified layer on one side thereof (A4100 manufactured by ToyoBoseki) was unrolled to provide a substrate. Next, a transparentconductive layer was formed on the adhesion modified surface of the PETfilm.

Conditions for forming the transparent conductive layer were as follows:a pressure was 0.4 Pa in sputtering; the flow rate of Ar was 200 sccm;and the flow rate of oxygen was 3 sccm. A power of 3 W/cm² was appliedto a target using RPG100 (manufactured by Japan ENI). In this case, apositive voltage pulse having a pulse width of 2 μsec and a pulsefrequency of 100 kHz was applied to suppress the occurrence of abnormalelectric discharge.

Note that the temperature dependency and separation distance dependencyof the eddy current sensor were previously measured to prepare acalibration curve. The feed speed of the film and the flow rate ofoxygen were adjusted based on the calibration curve while sequentiallymonitoring the measurement results of the eddy current-type surfaceresistance measuring device so that the center of the surface resistanceof the film was located at 250 Ω/□. The thickness of the transparentconductive layer was from 22 to 27 nm at the time of production of atransparent conductive film roll. Further, at the time of production ofthe transparent conductive film roll, the surface resistance value ofthe conductive layer was output over 100 m at positions which werelocated at the middle portion in a lateral direction thereof, positionswhich were located at a distance of 500 mm from the middle portion tothe right, and positions which were located at a distance of 500 mm fromthe middle portion to the left, and these positions were separated in 10m intervals in a longitudinal direction thereof. The measurement resultsby the eddy current-type surface resistance measuring device are shownin FIG. 5. The distribution uniformity of the surface resistance D ofthe conductive film was 0.03.

The resultant transparent conductive film roll was slit into 16 slitrolls each having a width of 600 mm and a length of 100 m. Theassessment results of the resultant transparent conductive film roll areshown in Table 1.

A 200 mm×300 mm rectangle of transparent conductive film was cut outfrom the slit roll of transparent conductive film. The rectangulartransparent conductive film was used as one panel plate and a silverpaste was printed on opposite ends thereof (sides having a length of 200mm). A transparent conductive glass (S500 manufactured by Nippon Soda)having a 20-nm thick indium-tin mixed oxide thin film (tin oxidecontent: 10% by weight), which had been provided on the glass substrateby plasma CVD, was cut into a 200 mm×300 mm rectangle as the other panelplate. A silver paste was printed on opposite ends of the glass panel(sides having a length of 300 mm). The two panel plates were disposedvia epoxy beads having a diameter of 30 μm so that the transparentconductive layers faced each other, to produce a touch panel. FIG. 13shows a cross-sectional view of the resultant touch panel. The result ofassessment of the touch panel is shown in Table 2 and FIG. 11.

Example 2

A PET film (HC101 manufactured by Toyo Boseki) having a clear hardcoating layer having a thickness of 192 μm on one side thereof was usedas a plastic film. A transparent conductive film roll and a touch panelwere obtained as in Example 1, except that a transparent conductivelayer was formed on the other side with respect to the hard coat layer.The results are shown in Tables 1 and 2. As in Example 1, at the time ofproduction of the transparent conductive film roll, the surfaceresistance value of the conductive layer was output over 100 m atpositions which were located at the middle portion in a lateraldirection thereof, positions which were located at a distance of 500 mmfrom the middle portion to the right, and positions which were locatedat a distance of 500 mm from the middle portion to the left, and thesepositions were separated in 10 m intervals in a longitudinal directionthereof. The measurement results by an eddy current-type surfaceresistance measuring device are shown in FIG. 6. The distributionuniformity of the surface resistance D of the conductive film was 0.09.

Example 3

A photopolymerization initiator-containing acrylic resin (Seika BeamEXF-01J manufactured by Dainichiseika Colour & Chemicals Mfg.) was addedto a mixed solvent of toluene and MEK (8:2 by weight) to a solidconcentration of 50% by weight. The mixture was stirred to afford ahomogeneous solution. Thus, application solution A was prepared.

Next, a PET film roll having a size of 1300 mm in width, 850 m in lengthand 188 μm in thickness and having an adhesion-modified layer on oneside thereof (A4100 manufactured by Toyo Boseki) was unrolled.Application solution A was applied to the adhesion modifying layer ofthe film to a thickness of 5 μm by Mayer bar, followed by drying at 80°C. for 1 min. The film was then irradiated with ultraviolet light usingan ultraviolet irradiating device (UB042-5AM-W manufactured byEyegraphics) (light amount: 300 mJ/cm²) to cure the applied film. Inaddition, heat treatment was performed at 180° C. for 1 min to reducethe volatile component. The PET film roll having the cured layer on oneside thereof was rolled up. The roll was prepared as a substrate.

The PET film roll having the cured layer on one side thereof was used asa substrate as in Example 1 to obtain a transparent conductive film rolland a touch panel, except that a transparent conductive layer was formedon a surface of the cured layer. The results are shown in Tables 1 and2.

As in Example 1, at the time of production of the transparent conductivefilm roll, the surface resistance value of the conductive layer wasoutput over 100 m at positions which were located at the middle portionin a lateral direction thereof, positions which were located at adistance of 500 mm from the middle portion to the right, and positionswhich were located at a distance of 500 mm from the middle portion tothe left, and these positions were separated in 10 m intervals in alongitudinal direction thereof. The measurement results by an eddycurrent-type surface resistance measuring device are shown in FIG. 7.The distribution uniformity of the surface resistance D of theconductive film was 0.02.

Example 4

A transparent conductive film roll and a touch panel were produced as inExample 1, except that the feed speed of the film and the flow rate ofoxygen were adjusted so that the center of the surface resistance of thefilm was located at 1000 Ω/□ using a tin-antimony mixed oxide (ATO)target (containing 5% by weight of antimony oxide, manufactured byMitsui Mining And Smelting) instead of ITO target, and the flow rate ofoxygen was changed from 3 sccm to 5 sccm. The results are shown inTables 1 and 2. The thickness of the transparent conductive layer wasfrom 95 to 110 nm at the time of production of the transparentconductive film roll.

As in Example 1, at the time of production of the transparent conductivefilm roll, the surface resistance value of the conductive layer wasoutput over 100 m at positions which were located at the middle portionin a lateral direction thereof, positions which were located at adistance of 500 mm from the middle portion to the right, and positionswhich were located at a distance of 500 mm from the middle portion tothe left, and these positions were separated in 10 m intervals in alongitudinal direction thereof. The measurement results by an eddycurrent-type surface resistance measuring device are shown in FIG. 8.The distribution uniformity of the surface resistance D of theconductive film was 0.10.

Example 5

A transparent conductive film roll and a touch panel were produced as inExample 1, except that a non-contact surface resistance measuring deviceincorporating a temperature sensor and a separation distance sensor iscontinuously reciprocated in a lateral direction of a conductive film tomeasure the surface resistance of the conductive film at three points: amiddle portion in a lateral direction of the film; and at a distance of500 mm from the middle portion to the right and left, instead ofproviding three non-contact surface resistance measuring devices atseparated positions on the conductive film of the transparent conductivefilm. The results are shown in Tables 1 and 2.

As in Example 1, at the time of production of the transparent conductivefilm roll, the surface resistance value of the conductive layer wasoutput over 100 m at positions which were located at the middle portionin a lateral direction thereof, positions which were located at adistance of 500 mm from the middle portion to the right, and positionswhich were located at a distance of 500 mm from the middle portion tothe left, and these positions were separated in 10 m intervals in alongitudinal direction thereof. The measurement results by an eddycurrent-type surface resistance measuring device are shown in FIG. 14.The distribution uniformity of the surface resistance D of theconductive film was 0.03.

Comparative Example 1

Comparative Example 1 was the same as Example 1, except that eddycurrent-type surface resistance measuring devices which did not comprisea temperature sensor and a separation distance sensor were used(provided at a total of three points: a middle portion in a lateraldirection of the film; and at a distance of 500 mm from the middleportion to the right and left). The results are shown in Tables 1 and 2and FIG. 12.

As in Example 1, at the time of production of the transparent conductivefilm roll, the surface resistance value of the conductive layer wasoutput over 100 m at positions which were located at the middle portionin a lateral direction thereof, positions which were located at adistance of 500 mm from the middle portion to the right, and positionswhich were located at a distance of 500 mm from the middle portion tothe left, and these positions were separated in 10 m intervals in alongitudinal direction thereof. The measurement results by the eddycurrent-type surface resistance measuring device are shown in FIG. 9.The distribution uniformity of the surface resistance D of theconductive film was 0.22.

Comparative Example 2

Comparative Example 2 was the same as Example 1, except that a monitorfor calculating the surface resistance of a film based on a resistancevalue between two insulation free rolls was used instead of eddycurrent-type surface resistance measuring devices. The results are shownin Tables 1 and 2.

As in Example 1, at the time of production of the transparent conductivefilm roll, the surface resistance value of the conductive layer wasoutput over 100 m at positions which were located at the middle portionin a lateral direction thereof, positions which were located at adistance of 500 mm from the middle portion to the right, and positionswhich were located at a distance of 500 mm from the middle portion tothe left, and these positions were separated in 10 m intervals in alongitudinal direction thereof. The measurement results by an eddycurrent-type surface resistance measuring device are shown in FIG. 10.The distribution uniformity of the surface resistance D of theconductive film was 0.33.

TABLE 1 Slit Surface resistance distribution uniformity D of conductivefilm roll Example Example Example Example Example ComparativeComparative No. 1 2 3 4 5 Example 1 Example 2 1 0.03 0.09 0.02 0.10 0.030.22 0.33 2 0.03 0.11 0.04 0.12 0.03 0.23 0.32 3 0.05 0.05 0.06 0.160.05 0.26 0.29 4 0.02 0.12 0.02 0.17 0.02 0.34 0.25 5 0.06 0.06 0.050.12 0.06 0.23 0.33 6 0.08 0.08 0.07 0.18 0.08 0.25 0.29 7 0.03 0.130.09 0.12 0.03 0.36 0.36 8 0.05 0.15 0.02 0.16 0.05 0.24 0.28 9 0.040.06 0.09 0.18 0.04 0.21 0.26 10 0.08 0.16 0.10 0.11 0.08 0.36 0.31 110.03 0.06 0.09 0.11 0.03 0.25 0.30 12 0.05 0.13 0.12 0.17 0.05 0.22 0.2913 0.06 0.05 0.08 0.12 0.06 0.23 0.27 14 0.03 0.08 0.09 0.09 0.03 0.280.25 15 0.08 0.03 0.10 0.09 0.08 0.23 0.24 16 0.05 0.12 0.02 0.02 0.050.21 0.26

TABLE 2 Pattern recognition deviation rate (%) Example 1 0.32 Example 20.86 Example 3 0.45 Example 4 0.76 Example 5 0.32 Comparative 2.51Example 1 Comparative 3.68 Example 2

According to the above-described results, the following was found.

In Examples 1 to 5, the surface resistance distribution of thetransparent conductive layer in the slit roll of the transparentconductive film is uniform in both the longitudinal and lateraldirections. Therefore, for example, input patterns can be accuratelyrecognized by the touch panel produced from the slit roll of thetransparent conductive film of Example 1.

In contrast, the surface resistance distribution of the transparentconductive layer of Comparative Example 1 had insufficient uniformity inthe longitudinal direction and that of Comparative Example 2 had insufficient uniformity in the lateral direction. Therefore, for example,the touch panel produced from the slit roll of the transparentconductive film of Comparative Examples 1 or 2 had a high patternrecognition deviation rate and was thus inadequate.

INDUSTRIAL APPLICABILITY

A transparent conductive film roll having quality, such as surfaceresistance or the like, which is uniform in longitudinal and lateraldirections thereof, is obtained, leading to excellent functionalstability, such as less character or pattern recognition deviation rateor the like, when the transparent conductive film roll is used in afinal product, such as a touch panel or the like.

1. A method for producing a transparent conductive film roll having awidth of from 300 mm to 1300 mm and a length of from 10 m to 1000 m, andhaving a transparent conductive layer on at least one side thereof usinga rolled-up film forming device, wherein the rolled-up film formingdevice has a non-contact surface resistance measuring devicetherewithin, a surface resistance of the transparent conductive layer issequentially measured in line at a plurality of positions in each oflongitudinal and lateral directions of the film while forming thetransparent conductive layer, and conditions for forming the transparentconductive layer are regulated so that the surface resistance thereof isuniformly distributed.
 2. A transparent conductive film roll productionmethod according to claim 1, wherein the non-contact surface resistancemeasuring device mainly comprises an eddy current generating sectionwhich is placed at a predetermined distance from the transparentconductive layer, faces the transparent conductive layer and flows aneddy current in the transparent conductive layer, an eddy currentdetecting section which is separated from the transparent conductivelayer and detects the eddy current flowing through the transparentconductive layer, a temperature detecting section which detects atemperature of the eddy current generating section or the eddy currentdetecting section, and a calculating means which calculates the surfaceresistance of the transparent conductive layer based on a result ofdetection by the eddy current detecting section and a result ofdetection by the temperature detecting section where a voltage appliedto the eddy current generating section is constant, wherein when theresult of detection by the temperature detecting section is deviatedfrom a reference temperature, the calculating means calculates an amountof an increase or decrease in the eddy current caused by the deviationfrom the reference temperature and adds or subtracts the amount of theincrease or decrease in the eddy current to or from the result ofdetection by the eddy current detecting section to correct the value ofthe eddy current and calculates the surface resistance of thetransparent conductive layer based on the corrected value of the eddycurrent.
 3. A transparent conductive film roll production methodaccording to claim 1, wherein a plurality of non-contact surfaceresistance measuring devices are provided in the lateral direction ofthe film.
 4. A transparent conductive film roll production methodaccording to claim 1, wherein the non-contact surface resistancemeasuring device is continuously reciprocated in the lateral directionof the film.